Conventional gravity-operated flush toilets have several basic components. The porcelain or china components include a bowl and a water tank mounted on top of a rear portion of the bowl. The bowl and tank can be separate pieces bolted together to form a two-piece toilet. Other gravity-operated flush toilets are made as a one-piece toilet in which the bowl and tank are made as one continuous integral piece of china.
More importantly, the plumbing components of a gravity-operated flush toilet include a fill valve in the tank which is connected to a water supply line, a flush valve surrounding a drain hole in the bottom of the tank that communicates with the bowl, and a flapper valve that normally closes and seals the flush valve or, more precisely, the main flush valve orifice.
Toilet flapper valves are typically formed as a single structure having a rim for sealing the main flush valve orifice with the flapper valve rim following flushing. The flapper valve is often formed of a soft elastomeric material and is hinged to allow the valve to be pivotally moved upwardly and away from the main flush valve orifice by means of a chain that is connected to the flush handle on the outside of the tank. Once the tank empties, the flapper valve then returns to a position where it seals the main flush valve orifice, the rim of soft elastomeric material forming a sealing area about that main flush valve orifice.
Such toilet flapper valves are also typically formed to include a ballast structure which is a dome-like or cone-shaped structure disposed within the rim of the flapper valve and which controls the buoyancy of the flapper valve. The buoyancy of a flapper valve is an important function because it determines how much or how little water is used to empty the water tank upon flushing, thus creating water conservancy issues. The buoyancy of the flapper valve is determined by how quickly air is allowed to escape from the ballast.
Therefore, one way that the buoyancy of the flapper valve ballast can be controlled is by controlling the rate at which air within the ballast can flow out of the ballast. This can be done by creating and/or adjusting the size of an aperture at a point within the flapper valve ballast. Another way that the buoyancy of the flapper valve ballast can be controlled is by controlling the rate at which water can flow back into the ballast.
In the experience of this inventor, flapper valves of current manufacture do not provide an easy-to-use and two-way adjustable flapper valve which combines both functionalities into a single structure.